Rewrite std::string("") to std::string(), Linux edition.

chrome/test/chromedriver/key_converter.cc

Index: chrome/test/chromedriver/key_converter.cc
diff --git a/chrome/test/chromedriver/key_converter.cc b/chrome/test/chromedriver/key_converter.cc
index 64c6099dbeafade2b641902342e03c58de53a536..49b95f36e627bb0d965b88115b61ecf310bd3b15 100644
--- a/chrome/test/chromedriver/key_converter.cc
+++ b/chrome/test/chromedriver/key_converter.cc
@@ -158,11 +158,13 @@ bool KeyCodeFromShorthandKey(char16 key_utf16,
 }  // namespace
 
 KeyEvent CreateKeyDownEvent(ui::KeyboardCode key_code, int modifiers) {
-  return KeyEvent(kRawKeyDownEventType, modifiers, "", "", key_code);
+  return KeyEvent(
+      kRawKeyDownEventType, modifiers, std::string(), std::string(), key_code);
 }
 
 KeyEvent CreateKeyUpEvent(ui::KeyboardCode key_code, int modifiers) {
-  return KeyEvent(kKeyUpEventType, modifiers, "", "", key_code);
+  return KeyEvent(
+      kKeyUpEventType, modifiers, std::string(), std::string(), key_code);
 }
 
 KeyEvent CreateCharEvent(const std::string& unmodified_text,